JPH0221046B2 - - Google Patents
Info
- Publication number
- JPH0221046B2 JPH0221046B2 JP56029550A JP2955081A JPH0221046B2 JP H0221046 B2 JPH0221046 B2 JP H0221046B2 JP 56029550 A JP56029550 A JP 56029550A JP 2955081 A JP2955081 A JP 2955081A JP H0221046 B2 JPH0221046 B2 JP H0221046B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- incident angle
- thin film
- substrate
- recording medium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000005291 magnetic effect Effects 0.000 claims description 110
- 239000010409 thin film Substances 0.000 claims description 43
- 239000000758 substrate Substances 0.000 claims description 32
- 238000001704 evaporation Methods 0.000 claims description 5
- 230000008020 evaporation Effects 0.000 claims description 5
- 239000007769 metal material Substances 0.000 claims description 4
- 239000010410 layer Substances 0.000 description 28
- 238000000151 deposition Methods 0.000 description 15
- 230000008021 deposition Effects 0.000 description 13
- 238000000034 method Methods 0.000 description 13
- 239000010408 film Substances 0.000 description 11
- 230000003746 surface roughness Effects 0.000 description 9
- 230000005294 ferromagnetic effect Effects 0.000 description 8
- 238000007740 vapor deposition Methods 0.000 description 8
- -1 CrO 2 Chemical class 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 229910020630 Co Ni Inorganic materials 0.000 description 4
- 229910002440 Co–Ni Inorganic materials 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 229920000139 polyethylene terephthalate Polymers 0.000 description 4
- 239000005020 polyethylene terephthalate Substances 0.000 description 4
- 238000007738 vacuum evaporation Methods 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 239000011241 protective layer Substances 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- 239000004952 Polyamide Substances 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 230000005347 demagnetization Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000010894 electron beam technology Methods 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 239000000696 magnetic material Substances 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 229920002284 Cellulose triacetate Polymers 0.000 description 1
- 229910020637 Co-Cu Inorganic materials 0.000 description 1
- 229910020707 Co—Pt Inorganic materials 0.000 description 1
- 229910020710 Co—Sm Inorganic materials 0.000 description 1
- 229910020514 Co—Y Inorganic materials 0.000 description 1
- 229910017061 Fe Co Inorganic materials 0.000 description 1
- 229910017060 Fe Cr Inorganic materials 0.000 description 1
- 229910002544 Fe-Cr Inorganic materials 0.000 description 1
- 229910002549 Fe–Cu Inorganic materials 0.000 description 1
- 229910052688 Gadolinium Inorganic materials 0.000 description 1
- 229910018657 Mn—Al Inorganic materials 0.000 description 1
- 229910018054 Ni-Cu Inorganic materials 0.000 description 1
- 229910018481 Ni—Cu Inorganic materials 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229920002433 Vinyl chloride-vinyl acetate copolymer Polymers 0.000 description 1
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000000445 field-emission scanning electron microscopy Methods 0.000 description 1
- 229920002457 flexible plastic Polymers 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000006247 magnetic powder Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 229920003207 poly(ethylene-2,6-naphthalate) Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 239000011112 polyethylene naphthalate Substances 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920005749 polyurethane resin Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000005019 vapor deposition process Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
- G11B5/851—Coating a support with a magnetic layer by sputtering
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Magnetic Record Carriers (AREA)
- Manufacturing Of Magnetic Record Carriers (AREA)
Description
本発明は斜め蒸着による強磁性金属薄膜を磁気
記録層として備えてなる磁気記録媒体に関するも
ので、特に、磁気特性および耐候性に優れた磁気
記録媒体に関する。さらに本発明は方向性異方性
の小さい上記磁気記録媒体に関する。
従来より磁気記録媒体としては非磁性支持体上
にγ−Fe2O3、Coをドープしたγ−Fe2O3、
Fe3O4、CoをドープしたFe3O4、γ−Fe2O3と
Fe3O4のベルトライド化合物、CrO2等の磁性粉末
あるいは強磁性合金粉末等の粉末磁性材料を塩化
ビニル−酢酸ビニル共重合体、スチレン−ブタジ
エン共重合体、エポキシ樹脂、ポリウレタン樹脂
等の有機バインダー中に分散せしめたものを塗布
し乾燥させる塗布型のものが広く使用されて来
た。しかし近年高密度記録への要求の高まりと共
に真空蒸着、スパツタリング、イオンプレーテイ
ング等のベーパーデポジシヨン法あるいは電気メ
ツキ、無電解メツキ等のメツキ法により形成され
る強磁性合金薄膜を磁気記録層とする、バインダ
ーを使用しないいわゆる非バインダー型磁気記録
媒体が注目を浴び、実用化への努力が種々行なわ
れている。
従来の塗布型の磁気記録媒体では、主として強
磁性金属より飽和磁化の小さい金属酸化物を磁性
材料として使用していたため、高密度記録に必要
な薄膜化は信号出力の低下をもたらすため限界が
あり、かつその製造工程も複雑で、溶剤回収ある
いは公害防止のための大きな付帯設備を要すると
いう欠点を有していた。一方、非バインダー型の
磁気記録媒体は前記酸化物より大きな飽和磁化を
有する強磁性金属をバインダーのような非磁性物
質を含有しない状態で薄膜として形成せしめるた
め、高密度記録化のために超薄形にできるという
利点を有し、しかもその製造工程は簡単である。
高密度記録用の磁気記録媒体に要求される条件
の１つとして、高抗磁力化、薄形化が理論的に
も、実験的にも提唱されており、前記塗布型の磁
気記録媒体よりも一桁小さい薄型化が前記非バイ
ンダー型の磁気記録媒体は容易で、飽和磁束密度
も大きい。
特に真空蒸着による方法はメツキの場合のよう
な排液処理を必要とせず製造工程も簡単で膜の析
出速度も大きくできるため、非常にメリツトが大
きい。真空蒸着によつて磁気記録媒体に望ましい
抗磁力および角型性を有する磁性膜を製造する方
法としては米国特許3342632号、同3342633号等に
述べられている斜め蒸着法が知られている。この
方法によると、基体に対して入射する蒸気流の入
射角が大きいほど実抗磁力の媒体が得られる。し
かしながら入射角が大きいと蒸着効率が低下する
という現象があり生産上問題である。
さらに強磁性金属薄膜から成る磁気記録媒体に
かかわる大きな問題として腐蝕および摩耗に対す
る強度、走行安定性がある。磁気記録媒体は磁気
信号の記録再生および消去の過程において磁気ヘ
ツドと高速相対運動のもとにおかれるが、その際
走行がスムーズにしかも安定に行なわれねばなら
ぬし、同時にヘツドとの接触による摩耗もしくは
破壊が起こつてはならない。又磁気記録媒体の保
存中に腐蝕等による経時変化によつて記録された
信号の減少あるいは消失があつてはならないこと
も要求される。耐久性、耐候性を向上させる方法
として保護層を設けることが検討されてはいるが
前記ヘツドと磁性層間の間隙損失のために保護層
の厚みを大きくできないという制約もあるため磁
性膜そのものにも耐久性、耐候性を備えさせるこ
とが必要である。
さらに又、強磁性金属薄膜を備えた磁気記録媒
体においては高密度記録媒体としての長所を生か
すために、表面が平坦な支持体上に磁性膜を設け
る必要があるが、表面が平坦な支持体を使用する
場合には充分な耐久性、耐候性が得られないとい
う問題があつた。
また従来行なわれてきたように斜め入射蒸着磁
性薄膜を単に一層設けてなる磁気記録媒体では、
磁気ヘツドに対する相対運動時の往路、復路での
電磁変換特性、走行性等が大きく異なるという欠
点を有していた。このように磁気記録媒体が、軸
異方性（axial anisotropy）ではなく、方向異方
性（directional anisotropy）を有する点は実用
上大きな問題である。
本発明の目的は上記の欠点が改良されてなると
共に電磁変換特性のすぐれた磁気記録媒体を提供
することである。
すなわち本発明の目的は、磁気特性がすぐれる
と共に耐摩耗性、耐候性にすぐれ電磁変換特性上
も大きく改良された非バインダー型磁気記録媒体
を提供することである。さらに本発明の目的は方
向性異方性の小さい上記磁気記録媒体を提供する
ことである。
本発明は、蒸発源から蒸発せしめられた磁性金
属材料の蒸気流を移動する基体に斜めに蒸着して
なる磁気記録媒体において、該基体に対する該蒸
気流の入射角を高入射角から低入射角へと連続的
に変化させることにより蒸着磁性薄膜を形成させ
た後、次に該基体面の法線に関して対称な方向よ
り該基体に対する該蒸気流の入射角を低入射角か
ら高入射角へと連続的に変化させて蒸着磁性薄膜
を形成させることによつて少なくとも２層の磁性
薄膜を積層したことを特徴とする磁気記録媒体、
さらに前記基体として磁性薄膜を設けるべき表面
粗さ（γa）が0.012μm以下であるような可撓性基
体を用いてなることを特徴とする磁気記録媒体、
さらに前記磁気記録媒体において、磁性薄膜間に
非磁性層を介在させたことを特徴とする磁気記録
媒体によつて達成される。
本発明において斜め蒸着とは、基体表面の法線
に対し磁性金属材料の蒸気流をある入射角θをも
たせて入射させ基体表面上に磁性薄膜を析出させ
る方法である。本発明においては特に斜め蒸着に
より磁性薄膜を析出させる際、入射角を連続的に
変化させることを特徴とする磁気記録媒体であ
る。
以下、この蒸着プロセスを詳述する。前記基体
に最も近い層を形成させる際、磁性薄膜の析出ス
タート時には高入射角θmaxにて斜め蒸着を開始
し、前記基体の移動と共に低入射角θminへと連
続的に減少させるように変化させて第１の磁性薄
膜の析出をストツプさせる。次にこの第１の磁性
薄膜上に第２の磁性薄膜を繰り返して形成させ
る。なお、前記第２の磁性薄膜の析出スタート時
には前記第１の磁性薄膜と同一の方向に前記基体
を移動させながら、低入射角θminにて斜め蒸着
を開始し、前記基体の移動と共に入射角を連続的
に増加させるように変化させて、高入射角θmax
にて磁性薄膜の析出をストツプさせるものであ
り、前記基体表面の法線に関して対称な方向から
交互に斜め蒸着することにより、少なくとも２層
以上積層したことを特徴とする磁気記録媒体であ
る。
２層構造とした場合の磁気記録媒体の構成を図
式的に示した第１図において、支持体Ｂ上に第１
層１および第２層２の磁性薄膜が形成されてい
る。前記各層１，２の磁性薄膜は湾曲した傾斜柱
状構造１１，１２を有しており、前記第１層１の
柱状構造１１と前記第２層２の柱状構造１２の傾
斜方向は互いに交叉している。前記傾斜柱状構造
１１の前記支持体Ｂの法線に対する傾きは、前記
支持体Ｂに近い方で大きく、前記支持体Ｂより遠
くなるにつれて小さくなつて、全体が右側に傾き
下方に凸曲した湾曲状を呈している。また前記傾
斜柱状構造１２の前記支持体Ｂの法線に対する傾
きは、前記支持体Ｂに近い方で小さく、前記支持
体Ｂに遠くなるにつれて大きくなつて、全体が左
側に傾き上方に凸曲した湾曲状を呈している。な
お第１図は、２層構造を示しているが、２層以上
の多層構造であつてもよく、また前記各傾斜柱状
構造１１，１２の傾き及び湾曲が、第１図と異な
り逆例から見れば前述したものと正反対になるこ
とは明らかであろう。
本発明において入射角としては一般には45゜〜
90゜が望ましく、特に入射角θmaxは60゜〜90゜、入
射角θminは45゜〜75゜が望ましい。
本発明に用いられる磁性金属材料としては、
Fe、Co、Ni等の金属、あるいはFe−Co、Fe−
Ni、Co−Ni、Fe−Co−Ni、Fe−Rh、Fe−Cu、
Co−Cu、Co−Au、Co−Ｙ、Co−La、Co−Pr、
Co−Gd、Co−Sm、Co−Pt、Ni−Cu、Mn−
Bi、Mn−Sb、Mn−Al、Fe−Cr、Co−Cr、Ni
−Cr、Fe−Co−Cr、Ni−Co−Cr、Fe−Co−Ni
−Cr等の強磁性合金である。特に好ましいのは
CoあるいはCoを75重量％含有するような合金で
ある。積層してなる磁性薄膜の総厚さは、磁気記
録媒体として充分な出力を与え得る厚さおよび高
密度記録の充分行える薄さを必要とすることから
一般には約0.02μmから5.0μm、好ましくは
0.05μmから2.0μmである。各磁性薄膜の厚さは等
しく設計してもいいし、基体に最も近い磁性薄膜
の±50％の厚さで設けてもいい。
本発明における蒸着とは、上記米国特許第
3342632号の明細書等に述べられている通常の真
空蒸着の他、電界、磁界あるいは電子ビーム照射
等により蒸気流のイオン化、加速化等を行つて蒸
発分子の平均自由行程の大きい雰囲気にて支持基
体上に薄膜を形成させる方法をも含むものであつ
て、例えば当出願人による特開昭51−149008号明
細書に示されているような電界蒸着法、特公昭43
−11525号、特公昭46−20484号、特公昭47−
26579号、特公昭49−45439号、特開昭49−33890
号、特開昭49−34483号、特開昭49−54235号公報
に示されているようなイオン化蒸着法も本発明に
用いられる。
本発明に用いられる基体としてはポリエチレン
テレフタレート、ポリイミド、ポリアミド、ポリ
塩化ビニル、三酢酸セルロース、ポリカーボネー
ト、ポリエチレンナフタレートのようなプラスチ
ツクベースが好ましい。特に本発明においては表
面粗さ（γa）が0.012μm以下であるような上記可
撓性プラスチツクベースが好ましい。ここで表面
粗さ（γa）とはJIS−BO601の５項に示されてい
る中心線平均粗さで、カツトオフは0.25mmとす
る。さらに上記プラスチツクベース上に下塗り層
を設け、その表面粗さ（γa）を0.012μm以下とし
たものを基体として用いてもいい。
さらに本発明においては積層してなる磁性薄膜
の間に非磁性層を介在させてもいい。非磁性中間
層として好ましいのはCr、Si、Al、Mn、Bi、
Ti、Sn、Pb、In、Zn、Cuあるいはこれらの酸化
物、窒化物より構成される層である。
次に実施例をもつて本発明を具体的に説明する
が本発明はこれに限定されるものではない。
実施例 １
第２図に示したような巻取り式蒸着装置２０を
用いて、23μm厚のポリエチレンテレフタレート
フイルム上に後述する方法により斜め蒸着のコバ
ルト磁性薄膜を形成させて磁気テープを作製し
た。蒸発源２１，２３としては電子ビーム加熱式
蒸発源を使用し真空度７×10-5Torr中にて蒸着
を行つた。なお、２２はクーリングキヤンであ
る。磁性膜の全厚は2000Åとなるようにし、蒸着
の際の入射角設定はθmaxを90゜θminを60゜とした。
得られた磁気テープはVHS型VTRにて電磁変換
特性、スチル耐久性を測定した。磁気記録層の層
構成およびポリエチレンテレフタレートフイルム
の表面粗さを変化させた場合の磁気テープの磁気
特性、減磁、スチール耐久性、4MHzのビデオ出
力、テープの対ヘツド走行方向を正逆変化させた
時の4MHzのビデオ出力差を第１表に示す。磁気
テープの耐候性をみるために磁気テープを60℃、
90％相対湿度中に７日間保持した場合の飽和磁束
密度（Bm）の減少を測定した。第１表には７日
間上記環境中に保持した後の飽和磁束密度
（Bm）の当初の飽和磁束密度（Bm0）に対する
比（Bm7／Bm0）を１から引いた数値で示して
いる。
The present invention relates to a magnetic recording medium comprising a ferromagnetic metal thin film formed by oblique vapor deposition as a magnetic recording layer, and particularly to a magnetic recording medium having excellent magnetic properties and weather resistance. Furthermore, the present invention relates to the above magnetic recording medium having small directional anisotropy. Traditionally, magnetic recording media include γ-Fe 2 O 3 , Co-doped γ-Fe 2 O 3 on a non-magnetic support,
Fe 3 O 4 , Co-doped Fe 3 O 4 , γ-Fe 2 O 3 and
Powdered magnetic materials such as Fe 3 O 4 bertolide compounds, magnetic powders such as CrO 2 , or ferromagnetic alloy powders are combined with organic materials such as vinyl chloride-vinyl acetate copolymers, styrene-butadiene copolymers, epoxy resins, polyurethane resins, etc. Coating-type products have been widely used, in which the material is dispersed in a binder and then applied and dried. However, in recent years, with the increasing demand for high-density recording, magnetic recording layers are made of ferromagnetic alloy thin films formed by vapor deposition methods such as vacuum evaporation, sputtering, and ion plating, or plating methods such as electroplating and electroless plating. , so-called binder-free magnetic recording media that do not use a binder have attracted attention, and various efforts are being made to put them into practical use. Conventional coating-type magnetic recording media mainly use metal oxides, which have lower saturation magnetization than ferromagnetic metals, as magnetic materials, so there is a limit to the thinning required for high-density recording, as this results in a reduction in signal output. , and its manufacturing process is complicated, and it has the disadvantage of requiring large auxiliary equipment for solvent recovery and pollution prevention. On the other hand, non-binder type magnetic recording media are made by forming a thin film of ferromagnetic metal, which has a saturation magnetization higher than that of the oxide, without containing a non-magnetic substance such as a binder, so it is ultra-thin for high-density recording. It has the advantage of being easily shaped, and the manufacturing process is simple. As one of the conditions required for magnetic recording media for high-density recording, high coercive force and thinness have been proposed both theoretically and experimentally. The non-binder type magnetic recording medium can easily be made thinner by an order of magnitude, and has a high saturation magnetic flux density. In particular, the method using vacuum evaporation is very advantageous because it does not require drainage treatment as is the case with plating, the manufacturing process is simple, and the deposition rate of the film can be increased. As a method for manufacturing a magnetic film having coercive force and squareness desirable for magnetic recording media by vacuum deposition, an oblique deposition method described in US Pat. No. 3,342,632, US Pat. According to this method, the larger the angle of incidence of the vapor flow incident on the substrate, the more effectively a medium can be obtained. However, when the incident angle is large, the deposition efficiency decreases, which is a problem in production. Furthermore, major problems concerning magnetic recording media made of ferromagnetic metal thin films include strength against corrosion and abrasion, and running stability. During the process of recording, reproducing, and erasing magnetic signals, the magnetic recording medium is subjected to high-speed relative motion with the magnetic head, but at this time, it must travel smoothly and stably, and at the same time, it must be able to travel smoothly and stably. No wear or breakage shall occur. It is also required that the recorded signals should not decrease or disappear due to changes over time due to corrosion or the like while the magnetic recording medium is being stored. Providing a protective layer has been considered as a way to improve durability and weather resistance, but there is a constraint that the thickness of the protective layer cannot be increased due to the gap loss between the head and the magnetic layer, so it is difficult to increase the thickness of the protective layer. It is necessary to provide durability and weather resistance. Furthermore, in order to take advantage of the advantages of a magnetic recording medium equipped with a ferromagnetic metal thin film as a high-density recording medium, it is necessary to provide a magnetic film on a support with a flat surface. When using , there was a problem that sufficient durability and weather resistance could not be obtained. In addition, in the conventional magnetic recording medium in which a magnetic thin film is simply deposited at an oblique incidence,
It has the disadvantage that the electromagnetic conversion characteristics, running performance, etc. on the outward and return trips during relative movement with respect to the magnetic head are significantly different. The fact that magnetic recording media have directional anisotropy rather than axial anisotropy is a major problem in practice. An object of the present invention is to provide a magnetic recording medium which has improved the above-mentioned drawbacks and has excellent electromagnetic conversion characteristics. That is, an object of the present invention is to provide a non-binder type magnetic recording medium which has excellent magnetic properties, wear resistance, weather resistance, and greatly improved electromagnetic conversion characteristics. A further object of the present invention is to provide the above magnetic recording medium with small directional anisotropy. The present invention provides a magnetic recording medium in which a vapor flow of a magnetic metal material evaporated from an evaporation source is obliquely deposited on a moving substrate, in which the incident angle of the vapor flow with respect to the substrate is changed from a high incident angle to a low incident angle. After forming a deposited magnetic thin film by continuously changing the angle of incidence to the substrate, the angle of incidence of the vapor flow on the substrate is changed from a low incident angle to a high incident angle from a direction symmetrical with respect to the normal to the substrate surface. A magnetic recording medium characterized in that at least two magnetic thin films are laminated by continuously changing the evaporated magnetic thin film.
A magnetic recording medium further characterized in that the substrate is a flexible substrate having a surface roughness (γa) of 0.012 μm or less on which a magnetic thin film is to be provided;
Furthermore, the present invention is achieved by the magnetic recording medium characterized in that a nonmagnetic layer is interposed between the magnetic thin films. In the present invention, oblique deposition is a method in which a vapor flow of a magnetic metal material is made incident at a certain angle of incidence θ relative to the normal to the substrate surface to deposit a magnetic thin film on the substrate surface. In the present invention, the magnetic recording medium is characterized in that the incident angle is continuously changed when a magnetic thin film is deposited by oblique deposition. This vapor deposition process will be explained in detail below. When forming the layer closest to the substrate, oblique deposition is started at a high incident angle θmax at the start of deposition of the magnetic thin film, and as the substrate moves, the angle of incidence is gradually decreased to a low incident angle θmin. Stopping the deposition of the first magnetic thin film. Next, a second magnetic thin film is repeatedly formed on this first magnetic thin film. Note that when starting the deposition of the second magnetic thin film, oblique deposition is started at a low incident angle θmin while moving the substrate in the same direction as the first magnetic thin film, and as the substrate moves, the incident angle is changed. High incidence angle θmax by changing continuously to increase
This magnetic recording medium is characterized in that at least two or more layers are laminated by alternately diagonally depositing them from symmetrical directions with respect to the normal to the substrate surface. In FIG. 1, which schematically shows the structure of a magnetic recording medium with a two-layer structure, a first layer is placed on a support B.
A layer 1 and a second layer 2 of magnetic thin films are formed. The magnetic thin films of the respective layers 1 and 2 have curved inclined columnar structures 11 and 12, and the inclined directions of the columnar structures 11 of the first layer 1 and the columnar structures 12 of the second layer 2 cross each other. There is. The inclination of the inclined columnar structure 11 with respect to the normal line of the support body B is large near the support body B, and decreases as the distance from the support body B increases, so that the entire structure is tilted to the right and curved convexly downward. It is showing the condition. Further, the inclination of the inclined columnar structure 12 with respect to the normal line of the support body B is small near the support body B, and increases as the distance from the support body B increases, so that the entire structure is tilted to the left and convexly curved upward. It has a curved shape. Although FIG. 1 shows a two-layer structure, it may be a multilayer structure with two or more layers, and the inclination and curvature of each of the inclined columnar structures 11 and 12 differ from FIG. If you look at it, it will be obvious that it is the exact opposite of what was described above. In the present invention, the angle of incidence is generally 45°~
The angle of incidence θmax is preferably 60° to 90°, and the angle of incidence θmin is preferably 45° to 75°. The magnetic metal materials used in the present invention include:
Metals such as Fe, Co, Ni, or Fe−Co, Fe−
Ni, Co-Ni, Fe-Co-Ni, Fe-Rh, Fe-Cu,
Co-Cu, Co-Au, Co-Y, Co-La, Co-Pr,
Co−Gd, Co−Sm, Co−Pt, Ni−Cu, Mn−
Bi, Mn-Sb, Mn-Al, Fe-Cr, Co-Cr, Ni
−Cr, Fe−Co−Cr, Ni−Co−Cr, Fe−Co−Ni
-It is a ferromagnetic alloy such as Cr. Particularly preferred is
It is an alloy containing Co or 75% by weight of Co. The total thickness of the laminated magnetic thin film is generally about 0.02 μm to 5.0 μm, preferably about 0.02 μm to 5.0 μm, since it needs to be thick enough to provide sufficient output as a magnetic recording medium and thin enough to perform high-density recording.
It is 0.05μm to 2.0μm. The thickness of each magnetic thin film may be designed to be equal, or the thickness may be ±50% of the thickness of the magnetic thin film closest to the substrate. Vapor deposition in the present invention refers to
In addition to the usual vacuum evaporation described in the specification of No. 3342632, vapor flow is ionized and accelerated by electric field, magnetic field, electron beam irradiation, etc., and the vaporized molecules are supported in an atmosphere with a large mean free path. It also includes a method of forming a thin film on a substrate, such as the electric field vapor deposition method as disclosed in Japanese Patent Application Laid-open No. 149008/1983 by the applicant, and the method of forming a thin film on a substrate.
−11525, Special Publication No. 11525, Special Publication No. 20484, Special Publication No. 1977−
No. 26579, JP 49-45439, JP 49-33890
Ionized vapor deposition methods such as those disclosed in JP-A-49-34483 and JP-A-49-54235 can also be used in the present invention. Preferred substrates for use in the present invention are plastic bases such as polyethylene terephthalate, polyimide, polyamide, polyvinyl chloride, cellulose triacetate, polycarbonate, and polyethylene naphthalate. Particularly in the present invention, the above-mentioned flexible plastic base having a surface roughness (γa) of 0.012 μm or less is preferable. Here, the surface roughness (γa) is the center line average roughness shown in Section 5 of JIS-BO601, and the cutoff is 0.25 mm. Furthermore, an undercoat layer may be provided on the plastic base, and the surface roughness (γa) of the undercoat layer may be set to 0.012 μm or less, and this may be used as the substrate. Furthermore, in the present invention, a nonmagnetic layer may be interposed between the laminated magnetic thin films. Preferred materials for the nonmagnetic intermediate layer are Cr, Si, Al, Mn, Bi,
A layer composed of Ti, Sn, Pb, In, Zn, Cu, or their oxides or nitrides. Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto. Example 1 A magnetic tape was produced by forming a cobalt magnetic thin film by diagonal deposition on a 23 μm thick polyethylene terephthalate film by the method described below using a winding type deposition apparatus 20 as shown in FIG. Electron beam heating type evaporation sources were used as the evaporation sources 21 and 23, and the evaporation was performed in a vacuum of 7×10 −5 Torr. Note that 22 is a cooling can. The total thickness of the magnetic film was set to 2000 Å, and the incident angle during vapor deposition was set to θmax of 90° and θmin of 60°.
The obtained magnetic tape was measured for electromagnetic conversion characteristics and still durability using a VHS type VTR. Magnetic properties of magnetic tape, demagnetization, steel durability, 4MHz video output, and forward/reverse running direction of the tape relative to the head when changing the layer structure of the magnetic recording layer and the surface roughness of the polyethylene terephthalate film. Table 1 shows the difference in video output at 4MHz. To check the weather resistance of magnetic tape, heat it to 60℃.
The decrease in saturation magnetic flux density (Bm) was measured when kept in 90% relative humidity for 7 days. Table 1 shows the ratio (Bm 7 /Bm 0 ) of the saturation magnetic flux density (Bm) to the initial saturation magnetic flux density (Bm 0 ) after being kept in the above environment for 7 days as a value subtracted from 1. .
【表】
なお、前記コバルト磁性薄膜の積層方法とし
て、先ず前記基体Ｂをクーリングキヤン２２によ
り矢印CWの方向に走行させながら前記基体Ｂに
対する蒸気流Ｖの入射角を第１層については高入
射角から低入射角へと、第２層については前記基
体Ｂを矢印CCWの方向に走行させながら低入射
角から高入射角へと連続的に変化させて蒸着し
た。磁性薄膜をその柱状構造が交差するように積
層してなる磁気テープは、単層の場合に比べて磁
気特性が良いばかりでなく耐候性、耐久性、出
力、ノイズにおいてすぐれていることが明らかで
ある。特に表面粗さ（γa）が0.012μm以下のプラ
スチツクベース上に上記積層磁性薄膜を設けてな
る磁気テープは耐候性、耐久性、再生出力がさら
に向上することがわかる。
さらに本発明者等は、このような特性の向上の
原因について鋭意研究に努めた結果、上記積層磁
性薄膜の表面構造と密接な関連があることをつき
とめた。すなわち、FE−SEMにより上記媒体の
表面を調べたところ単層の場合に比べて表面が非
常に緻密な構造になつていることが判明した。し
たがつて耐候性について言えば、減磁の原因とな
る酸素の侵入が表面が緻密なために阻まれ、耐候
性が向上すると推察される。
また耐久性については、表面が緻密になること
により、膜表面の硬度が増し、磁気ヘツドでこす
つても摩耗しにくくなり、耐久性が向上すると考
えられる。
実施例 ２
実施例１と同様に巻取り式蒸着装置２０を用い
て14μm厚のポリエチレンテレフタレートフイル
ム上に斜め蒸着によりCo−Cr（Cr：５重量％）磁
性薄膜を形成させて磁気テープを作製した。真空
度は８×10-5Torrとし、入射角θmaxを85゜、
θminを65゜とした。磁性膜の全厚は1500Åとなる
ように作製した。層構成および基体の表面粗さを
変化させた場合の磁気テープの特性は第２表のよ
うである。[Table] As a method of laminating the cobalt magnetic thin film, first, while the base body B is run in the direction of arrow CW by the cooling can 22, the incident angle of the vapor flow V with respect to the base body B is set at a high incident angle for the first layer. The second layer was deposited by continuously changing the incident angle from the low incident angle to the high incident angle while moving the substrate B in the direction of the arrow CCW. It is clear that magnetic tape, which is made by laminating magnetic thin films in such a way that their columnar structures intersect, not only has better magnetic properties than a single layer, but also has superior weather resistance, durability, output, and noise. be. In particular, it can be seen that the weather resistance, durability, and reproduction output of a magnetic tape formed by providing the above laminated magnetic thin film on a plastic base with a surface roughness (γa) of 0.012 μm or less are further improved. Furthermore, as a result of intensive research into the cause of such improvement in characteristics, the present inventors have found that there is a close relationship with the surface structure of the laminated magnetic thin film. That is, when the surface of the above medium was examined by FE-SEM, it was found that the surface had a very dense structure compared to the case of a single layer. Therefore, in terms of weather resistance, it is presumed that the dense surface prevents the entry of oxygen, which causes demagnetization, and improves weather resistance. As for durability, it is thought that by making the surface denser, the hardness of the film surface increases, making it less likely to wear even when rubbed with a magnetic head, and thus improving durability. Example 2 A magnetic tape was produced by forming a Co-Cr (Cr: 5% by weight) magnetic thin film on a 14 μm thick polyethylene terephthalate film by oblique vapor deposition using the winding type vapor deposition apparatus 20 in the same manner as in Example 1. . The degree of vacuum is 8×10 -5 Torr, the angle of incidence θmax is 85°,
θmin was set to 65°. The total thickness of the magnetic film was made to be 1500 Å. Table 2 shows the characteristics of the magnetic tape when the layer structure and surface roughness of the substrate were changed.
【表】
実施例 ３
実施例１と同様に巻取り式蒸着装置２０を用い
て14μm厚のポリアミドフイルム上に斜め蒸着に
よりCo−Ni（Ni：20重量％）磁性薄膜を形成さ
せて磁気テープを作製した。真空度は２×
10-5Torrとし、入射角θmaxを90゜、入射角θmin
を70゜とした。磁性膜の全厚は1800Åとなるよう
に作製した。層構成および基体の表面粗さを変化
させた場合の磁気テープの特性は第３表のようで
ある。磁気テープの特性は実施例１と同様にして
測定した。[Table] Example 3 A Co-Ni (Ni: 20% by weight) magnetic thin film was formed by diagonal deposition on a 14 μm thick polyamide film using the winding type deposition apparatus 20 in the same manner as in Example 1, and a magnetic tape was produced. Created. Vacuum degree is 2x
10 -5 Torr, incident angle θmax is 90°, incident angle θmin
was set to 70°. The total thickness of the magnetic film was made to be 1800 Å. Table 3 shows the properties of the magnetic tape when the layer structure and surface roughness of the substrate were changed. The characteristics of the magnetic tape were measured in the same manner as in Example 1.
【表】
以上の実施例から明らからように、移動する基
体に対する蒸気流の入射角を高入射角から低入射
角へと連続的に変化させることにより蒸着磁性薄
膜を形成させた後、次に基体面の法線に関して反
対側の方向より移動基体に対する蒸気流の入射角
を低入射角から高入射角へと連続的に変化させて
蒸着磁性薄膜を形成させることによつて少なくと
も２層積層してなる磁気記録媒体は、磁気特性、
耐候性、耐久性、再生出力、テープ走行方向によ
る再生出力差においてすぐれている。特に表面粗
さ（γa）が0.012μm以下のプラスチツクフイルム
上に上記磁性薄膜を設けてなる磁気テープは耐候
性、耐久性、再生出力においてさらにすぐれ蒸着
テープの実用化上、その利点は極めて大きい。[Table] As is clear from the above examples, after forming a vapor-deposited magnetic thin film by continuously changing the incident angle of the vapor flow to a moving substrate from a high incident angle to a low incident angle, At least two layers are laminated by forming a vapor-deposited magnetic thin film by continuously changing the incident angle of the vapor flow to the moving substrate from a low incident angle to a high incident angle from the opposite direction with respect to the normal to the substrate surface. A magnetic recording medium consisting of magnetic properties,
It has excellent weather resistance, durability, playback output, and playback output differences depending on the tape running direction. In particular, a magnetic tape formed by disposing the magnetic thin film on a plastic film with a surface roughness (γa) of 0.012 μm or less has excellent weather resistance, durability, and reproduction output, and has extremely great advantages in terms of practical application of vapor-deposited tape.
第１図は本発明による磁気記録体の層構成を示
す断面図、第２図は本発明の実施例において用い
た真空蒸着装置の要部断面図である。
１は第１の磁性薄膜、２は第２の磁性薄膜、Ｂ
は基体である。
FIG. 1 is a cross-sectional view showing the layer structure of a magnetic recording medium according to the present invention, and FIG. 2 is a cross-sectional view of essential parts of a vacuum evaporation apparatus used in an embodiment of the present invention. 1 is the first magnetic thin film, 2 is the second magnetic thin film, B
is the substrate.
Claims (1)
蒸気流を移動する基体に斜めに入射蒸着してなる
磁気記録媒体において、少なくとも前記基体に対
する前記蒸気流の入射角を高入射角から低入射角
へと連続的に変化させることにより形成せしめた
第１の蒸着磁性薄膜と、前記基体面の法線に関し
て対称な方向より該基体に対する前記蒸気流の入
射角を低入射角から高入射角へと連続的に変化さ
せて形成せしめた第２の蒸着磁性薄膜を、積層し
て成ることを特徴とする磁気記録媒体。 ２ 磁性薄膜を層設すべき表面の粗さ（γa）が
0.012μm以下であるような可撓性基体を具備して
成ることを特徴とする特許請求の範囲第１項記載
の磁気記録媒体。 ３ 前記各磁性薄膜間に非磁性層を介在させたこ
とを特徴とする特許請求の範囲第１項記載の磁気
記録媒体。[Scope of Claims] 1. In a magnetic recording medium in which a vapor flow of a magnetic metal material evaporated from an evaporation source is obliquely deposited on a moving substrate, at least the incident angle of the vapor flow with respect to the substrate is set to a high incidence. The first evaporated magnetic thin film is formed by continuously changing the incident angle from a low incident angle to a low incident angle, and the incident angle of the vapor flow to the substrate is changed from a low incident angle to a direction symmetrical with respect to the normal to the substrate surface. A magnetic recording medium comprising a second vapor-deposited magnetic thin film formed by continuously changing the incident angle to a high incident angle. 2 The roughness (γa) of the surface on which the magnetic thin film is to be layered is
2. The magnetic recording medium according to claim 1, comprising a flexible substrate having a thickness of 0.012 μm or less. 3. The magnetic recording medium according to claim 1, characterized in that a nonmagnetic layer is interposed between each of the magnetic thin films.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2955081A JPS57143730A (en) | 1981-03-02 | 1981-03-02 | Magnetic recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2955081A JPS57143730A (en) | 1981-03-02 | 1981-03-02 | Magnetic recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57143730A JPS57143730A (en) | 1982-09-06 |
| JPH0221046B2 true JPH0221046B2 (en) | 1990-05-11 |
Family
ID=12279244
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2955081A Granted JPS57143730A (en) | 1981-03-02 | 1981-03-02 | Magnetic recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57143730A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59119531A (en) * | 1982-12-25 | 1984-07-10 | Tdk Corp | Magnetic recording medium |
| JPS6047227A (en) * | 1983-08-24 | 1985-03-14 | Dainippon Printing Co Ltd | Magnetic recording medium |
| US4622271A (en) * | 1984-04-20 | 1986-11-11 | Fuji Photo Film Co., Ltd. | Magnetic recording medium |
| JPH01125714A (en) * | 1987-11-11 | 1989-05-18 | Sony Corp | Magnetic tape |
| JP2897840B2 (en) * | 1990-05-10 | 1999-05-31 | ティーディーケイ株式会社 | Magnetic recording media |
| JPH05101365A (en) * | 1991-03-22 | 1993-04-23 | Tdk Corp | Perpendicular magnetic recording medium and production thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5634139A (en) * | 1979-08-22 | 1981-04-06 | Ulvac Corp | Magnetic recording medium |
| JPS56134317A (en) * | 1980-03-25 | 1981-10-21 | Tdk Corp | Magnetic recording medium |
-
1981
- 1981-03-02 JP JP2955081A patent/JPS57143730A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5634139A (en) * | 1979-08-22 | 1981-04-06 | Ulvac Corp | Magnetic recording medium |
| JPS56134317A (en) * | 1980-03-25 | 1981-10-21 | Tdk Corp | Magnetic recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57143730A (en) | 1982-09-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4557944A (en) | Process of manufacturing a magnetic recording medium | |
| JPH0445889B2 (en) | ||
| JPH0123853B2 (en) | ||
| JPH0221046B2 (en) | ||
| JPS5814324A (en) | Magnetic recording medium | |
| JP2897840B2 (en) | Magnetic recording media | |
| JPH04259909A (en) | Magnetic recording medium | |
| JPH0328735B2 (en) | ||
| KR100233697B1 (en) | Magnetic recording medium | |
| JPH0546013B2 (en) | ||
| JPH0445888B2 (en) | ||
| JPH0381202B2 (en) | ||
| JPH0142046B2 (en) | ||
| JP3167128B2 (en) | Magnetic recording media | |
| JPH0766511B2 (en) | Magnetic recording medium | |
| JPS61187122A (en) | Magnetic recording medium | |
| JPH06139541A (en) | Magnetic recording medium | |
| JPH01124115A (en) | Magnetic recording medium and its production | |
| JP3491778B2 (en) | Magnetic recording media | |
| JP2002237027A (en) | Magnetic recording medium | |
| JP3167129B2 (en) | Magnetic recording media | |
| JPH061550B2 (en) | Method of manufacturing magnetic recording medium | |
| JP2001344736A (en) | Magnetic recording medium and magnetic recording method | |
| JP2004039078A (en) | Magnetic recording medium | |
| JPS61294635A (en) | Magnetic recording medium |